<?php
// case sensitive search

   $username = "jasoN";
   if (preg_match("([^a-z])",$username)){
   	echo "Username must be all lowercase! \n";
   }
   
   $username = "jason";
   if (preg_match("([^a-z])",$username)){
   	echo "Username must be all lowercase! \n";
   }else {
   	echo "doesn't match. \n";
   }

   
   $username = "jAason";
   if (preg_match("(^[a-z])",$username)){
   	echo "Username must be all lowercase! \n";
   }else {
   	echo "doesn't match.\n";
   }
?>